What is the significance of an Ankle-Brachial Index (ABI) of 0.91?

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Last updated: April 1, 2025View editorial policy

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From the Guidelines

An ABI of 0.91 is considered borderline and may indicate possible peripheral artery disease (PAD), particularly if there is a significant clinical suspicion, and further evaluation such as exercise ABI may be warranted 1. When interpreting the Ankle-Brachial Index (ABI), it's crucial to consider the clinical context and the patient's overall risk factors for peripheral artery disease.

  • The ABI is a useful diagnostic tool for PAD, with values ≤0.90 indicating PAD, and values >1.40 suggesting noncompressible arteries, often seen in patients with diabetes or advanced chronic kidney disease 1.
  • Borderline values, such as 0.91 to 0.99, may require additional testing, like exercise ABI, to confirm the diagnosis if clinical suspicion is high 1.
  • Clinical judgment plays a significant role in interpreting ABI results, as the pretest probability of PAD, based on symptoms, risk factors, and medical history, influences the optimal threshold for diagnosis 1.
  • The sensitivity of ABI can be increased by measuring it immediately after treadmill exercise, which can help in diagnosing PAD in patients with borderline ABI values 1. Given the information provided and the current guidelines, further evaluation is recommended for an ABI of 0.91, especially if there are symptoms or risk factors suggestive of PAD, to determine the need for treatment or lifestyle modifications to reduce the risk of cardiovascular events 1.

From the Research

Aspirin and Peripheral Arterial Disease

  • The efficacy of aspirin in patients with peripheral arterial disease (PAD) is uncertain, with some studies indicating it is less effective than in coronary artery disease 2.
  • Aspirin is still considered the first line of antiplatelet drug for secondary prevention of cardiovascular events in PAD patients, with clopidogrel as an effective alternative 2.
  • Dual antiplatelet therapy (DAPT) with aspirin and another antiplatelet drug may be beneficial in preventing complications after revascularization in PAD patients, but the optimal duration of DAPT is unclear 3.

Ankle-Brachial Index and PAD

  • The ankle-brachial pressure index (ABI) is a noninvasive tool used to diagnose PAD and predict adverse outcomes, with both low and high ABI values associated with increased cardiovascular mortality 4.
  • An ABI value of less than 0.90 is commonly used to define PAD, but the prognostic value of ABI in hospitalized medical patients is not fully understood 4.

Antithrombotic Treatment in PAD

  • Antithrombotic treatment, including antiplatelet therapy and anticoagulation, is used to prevent cardiovascular events in PAD patients, with the choice of treatment depending on the individual patient's risk factors and medical history 5.
  • Rivaroxaban plus aspirin has been shown to be effective in reducing total mortality and cardiovascular mortality in PAD patients, and may be considered for secondary prevention 5.

Future Perspectives on PAD Treatment

  • Novel antiplatelet agents and drug combinations are being developed for the treatment of PAD, with a focus on personalized antiplatelet therapy and reducing major adverse cardiovascular and limb-related events 6.
  • Statins are considered a standard of care in PAD patients due to their multiple actions, including plaque stabilization and antiinflammatory properties, and may be used in combination with antiplatelet therapy 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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